The present invention relates to controls that alter their operation to handle a plurality of models, in particular to controls that automatically identify the features of the model it is operating. Typically each control has handled only a single or very few of the models. Material and labor costs to include model identifying parts as well as the extra control I/O and program memory requirements to read these parts have exceeded the cost benefits realized by the volume production possible for a universal control.
The model options the present invention is concerned with affect the operation of the control. These options can generally be divided into two types, operator and preset. Operator options are chosen by the operator, typically with a control panel, to adjust the operation of the device. Preset options are fixed at the time of manufacture.
In prior art, deletion of an operator option is often accomplished by removing the switch connection used to select that option. Removing the switch connection eliminates the possibility of the operator selecting its option whether it be made by a momentary or position switch. This technique requires a unique switch connection for each operator option. It is not applicable to panels in which a single switch connection is used to choose from a group of options indicated by display elements.
Another prior method used to determine options, is to have the control read ID circuits, connections dedicated solely for identification purposes. Typically ID circuits determine preset options, such as brand and the number and type of output devices in the model. Each additional ID connection adds to the cost of the control. An ID connection may represent an individual feature or group of features. Individual connections allow the greatest flexibility as any combination of features is possible. Fewer group ID connections are required, but this approach requires more program space to look up what options belong to what connection while allowing fewer potential models.
Each option represented by an ID connection requires an additional circuit and a means to selectively read it. Placing ID connections on the control means it is not universal since the connections must be set for each model. Alternatively making ID connections off the control board enables the control to be universal but requires extra connectors, connections and wires to make the ID connections. In either case the extra I/O, connections, labor and parts to complete them and program memory to read and decode them raises the cost of the control. In U.S. Pat. No. 5,412,291 the wiring harness makes ID connections saving one set of connectors. This approach trades a universal control for the requirement of a unique harness for each model.
Another type of automatic identifying process is seen in personal computers. A PC scans components such as memory boards to identify the amount of memory present. The PC scans components designed to receive and transmit data to determine the options available. U.S. Pat. No. 6,739,145 uses this approach utilizing configuration memory to identify options. The output devices scanned by the present invention are not designed to transmit data to the control through the energizing circuit.
The present invention also relates to controls that scan the circuits of output devices to correctly and safely operate the output device. However while proir art shows controls altering their operation based on these scans, prior techniques do not teach using scans of output devices to identify the options of the model it is operating. In prior art scan of output device circuits allow proper operation of a model they do not identify the model. The control is either model specific or as in the case of U.S. Pat. No. 6,739,145 it uses others means to identify the model.